JP2005200737A - Method of forming transparent electroconductive film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method capable of forming a transparent electroconductive film, having satisfactory optical properties and electrical properties and having excellent mechanical resistance on a plastic film base material, highly safely in a high productivity, and to provide a transparent electroconductive film and an article having the transparent electroconductive film. <P>SOLUTION: In the method of forming the transparent electroconductive film under atmospheric pressure or under the pressure near the atmospheric pressure, reactive gas and discharge gas are introduced into a discharge space between electrodes, a high frequency electric field is applied to the space between the electrodes so as to be a plasma state, and, in the discharge space, a base material is exposed to the reactive gas in the plasma state to form a transparent electroconductive film on the base material, the reactive gas is a gaseous mixture comprising inorganic gas having at least one oxygen atom in the molecule and an organic metal compound, and the discharge gas is nitrogen. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is suitably used for various electronic elements such as liquid crystal display elements, organic electroluminescence elements (hereinafter referred to as organic EL elements), plasma display panels (hereinafter referred to as PDPs), electronic paper, touch panels, solar cells and the like. The present invention relates to a method for forming a transparent conductive film.

  Conventionally, transparent conductive films have been widely used for liquid crystal display elements, organic EL elements, solar cells, touch panels, electromagnetic wave shielding materials, infrared reflective films, and the like.

As the transparent conductive film, a metal thin film such as Pt, Au, Ag, or Cu, SnO ₂ , In ₂ O ₃ , CdO, ZnO ₂ , SnO ₂ : Sb, SnO ₂ : F, ZnO: Al, In ₂ O ₃ : A composite oxide film made of an oxide such as Sn and a dopant, or a non-oxide film such as chalcogenide, LaB ₆ , TiN, or TiC is used. Among them, an indium oxide film doped with tin (ITO film) is most widely used because it has excellent electrical characteristics and is easily processed by etching.

  These transparent conductive films can be formed by vacuum deposition, sputtering, ion plating, vacuum plasma CVD, spray pyrolysis, thermal CVD, sol-gel, or the like.

  2. Description of the Related Art In recent years, flat panel displays such as liquid crystal display elements and organic EL elements have been increased in area and definition, and a higher performance transparent conductive film has been demanded. In particular, in liquid crystal display elements, elements and devices having high electric field responsiveness are required, and for that purpose, transparent conductive films having high electron mobility are required. Moreover, in an organic EL element, since a current drive system is adopted, a transparent conductive film having a lower resistance is required.

Among the methods for forming the transparent conductive film, the vacuum deposition method and the sputtering method can obtain a low-resistance transparent conductive film, and industrially, the specific resistance value is 10 ⁻⁴ using a DC magnetron sputtering apparatus. An ITO film having excellent conductivity on the order of Ω · cm can be obtained.

  However, these physical fabrication methods (PVD method) are intended to grow a film by depositing a target substance on a substrate in a gas phase, and a vacuum apparatus must be used. It was expensive, and the raw material use efficiency was poor, the productivity was low, and it was difficult to obtain a large-area film. Furthermore, in order to obtain a low-resistance product, it is necessary to heat to 200 to 300 ° C. during film formation, and it is difficult to form a low-resistance transparent conductive film on a plastic film.

  The sol-gel method (coating method) not only requires many processes such as dispersion preparation, coating, and drying, but also requires the use of a binder resin because of its low adhesion to the substrate to be treated. Therefore, the transparency is deteriorated. Moreover, the electrical characteristics of the obtained transparent conductive film are also inferior compared with the case where the PVD method is used.

  The thermal CVD method forms a film by spraying vaporized raw materials or raw material solutions onto a substrate and thermally decomposing them. The apparatus is simple, the productivity is high, and a large area can be easily formed. However, there is a problem that the base material to be used is limited because high temperature treatment at 400 to 500 ° C. is usually required at the time of firing. In particular, film formation on a plastic film substrate was difficult.

  The above sol-gel method (coating method) is difficult to obtain a high-performance thin film, and as a method of overcoming the disadvantage that productivity is poor in a method using a vacuum apparatus, discharge is performed at atmospheric pressure or near atmospheric pressure. A method of forming a thin film on a substrate (hereinafter referred to as an atmospheric pressure plasma CVD method) by exciting a reactive gas with plasma is proposed. A technique for forming a film is disclosed.

  Various studies have been conducted on atmospheric pressure plasma CVD, and a high-quality transparent conductive film can be obtained by using a mixed gas containing a rare gas and a metal compound gas that forms a transparent conductive film. It has been understood (for example, JP-A-2002-155371 (Patent Document 1)). However, in the atmospheric pressure plasma CVD method, helium and argon used for the discharge gas are expensive, which causes a significant increase in cost.

In the atmospheric pressure plasma CVD method, when an inexpensive gas other than a rare gas is used as a discharge gas, for example, oxygen gas, nitrogen gas or carbon dioxide in an air component, the strength of an electric field for starting discharge (hereinafter, Although the electric field strength is high), a stable discharge cannot be obtained under a conventional high-frequency electric field, and it is difficult to form a thin film. For example, Japanese Patent Application Laid-Open No. 10-154598 uses a pulse electric field. Further, it is disclosed that a discharge can be achieved even with a gas having a high discharge starting electric field strength such as nitrogen gas, and Japanese Patent Application Laid-Open No. 11-191576 uses a nitrogen gas to provide a high frequency electric field and a low frequency electric field. An electronic component mounting method including a step of cleaning a base material with plasma generated by superposition is disclosed. Furthermore, JP-A-2001-74906 (Patent Document 2) describes an atmospheric pressure plasma method using N ₂ gas using a low-frequency 100 kHz pulse.

  A transparent conductive film can be formed at low cost by using the atmospheric pressure plasma method using these nitrogen gases as a discharge gas. However, a transparent conductive film formed using these nitrogen gases as a discharge gas has a high performance. I found it difficult.

  The reason for this is that when an active gas such as nitrogen gas is used, carbon (C) and nitrogen (N) are likely to be contained in the film as impurities (impurities), which lower the carrier density and mobility, and increase the resistivity. It is thought that it is to make it. In the method using nitrogen gas as the discharge gas, a transparent conductive film having performance equivalent to that of sputtering has not yet been obtained.

The inventors have reduced the N and C contained in the film by adding a specific inorganic gas containing oxygen atoms as the main component of the reactive gas, and have high performance in atmospheric pressure plasma using nitrogen gas. Succeeded in producing a transparent conductive film. This is comparable to the performance of the sputter-deposited transparent conductive film, and because it uses cheaper nitrogen gas, it can be manufactured at low cost and is a highly productive method.
JP 2002-155371 A JP 2001-74906 A

  Accordingly, an object of the present invention is to provide a method for forming a transparent conductive film, which has high safety, excellent productivity, good optical properties and electrical properties, and excellent mechanical resistance on a plastic film substrate. The object is to provide an article having a conductive film and a transparent conductive film.

(Claim 1)
Under an atmospheric pressure or a pressure near atmospheric pressure, a reactive gas and a discharge gas are introduced into the discharge space between the electrodes, a high frequency electric field is applied between the electrodes to form a plasma state, and the substrate is In a method of forming a transparent conductive film by exposing to a reactive gas in a plasma state and forming a transparent conductive film on a substrate, the reactive gas contains an inorganic gas having at least one oxygen atom in the molecule and an organometallic compound A method for forming a transparent conductive film, which is a gas and the discharge gas is nitrogen.

(Claim 2)
The oxygen concentration in the atmosphere around the discharge space including the space formed between the electrodes to which the high-frequency electric field is applied and the space in which the reactive gas in the plasma state formed by the applied high-frequency electric field is in contact with the substrate It is 5 volume% or less, The transparent conductive film formation method of Claim 1 characterized by the above-mentioned.

(Claim 3)
The method for forming a transparent conductive film according to claim 1, wherein the organometallic compound is an organometallic compound represented by the following general formula 1 or general formula 2.

[In General Formulas 1 and 2, M represents In, Sn, Zn, R ₁ and R ₂ each represents an alkyl group, an aryl group, or an alkoxyl group that may have a substituent, and R represents a hydrogen atom, Represents a substituent, and R may combine with R ₁ and R ₂ to form a ring. R ₃ represents an alkyl group or an aryl group each optionally having a substituent. n1 represents an integer, and n2 represents an integer. ]
(Claim 4)
The high-frequency electric field is a superposition of a first high-frequency electric field and a second high-frequency electric field;
Said first of said second high-frequency electric field than the frequency omega ₁ of the high-frequency electric field frequency omega ₂ is high, the strength V ₁ of the first high frequency electric field, strength V ₂ and the discharge start of the second high-frequency electric field The relationship with the electric field strength IV is
V ₁ ≧ IV> V ₂
Alternatively, the transparent conductive film forming method according to claim ₁ , wherein V ₁ > IV ≧ V ₂ is satisfied.
(Claim 5)
The method for forming a transparent conductive film according to claim 4, wherein the discharge space includes a first electrode and a second electrode facing each other.
(Claim 6)
The method for forming a transparent conductive film according to claim 4 or 5, wherein an output density of the second high-frequency electric field is 50 W / cm ² or less.
(Claim 7)
The method for forming a transparent conductive film according to claim 6, wherein an output density of the second high-frequency electric field is 20 W / cm ² or less.
(Claim 8)
The method for forming a transparent conductive film according to claim 4, wherein an output density of the first high-frequency electric field is 1 W / cm ² or more.
(Claim 9)
The method for forming a transparent conductive film according to any one of claims 4 to 8, wherein an output density of the first high-frequency electric field is 50 W / cm ² or less.
(Claim 10)
The method for forming a transparent conductive film according to claim 4, wherein at least the second high-frequency electric field is a sine wave.
(Claim 11)
The voltage for forming the first high-frequency electric field is applied to the first electrode, and the voltage for forming the second high-frequency electric field is applied to the second electrode. 11. The transparent conductive film forming method according to any one of 10 above.
(Claim 12)
The method for forming a transparent conductive film according to any one of claims 4 to 11, wherein 90 to 99.9% by volume of the total amount of gas supplied to the discharge space is discharge gas.
(Claim 13)
The method for forming a transparent conductive film according to any one of claims 4 to 12, wherein an output density of the second high-frequency electric field is 1 W / cm ² or more.
(Claim 14)
The method for forming a transparent conductive film according to claim 4, wherein the frequency ω ₁ is 200 kHz or less.
(Claim 15)
The method for forming a transparent conductive film according to claim 4, wherein the frequency ω ₂ is 800 kHz or more.
(Claim 16)
The method for forming a transparent conductive film according to claim 1, wherein the surface temperature of the substrate exposed to the reactive gas in the plasma state is 300 ° C. or less.
(Claim 17)
The method for forming a transparent conductive film according to claim 1, wherein the inorganic gas having at least one oxygen atom in the molecule is N ₂ O gas.
(Claim 18)
The specific resistance value of the transparent conductive film is 1 × 10 ⁻³ Ω · cm or less, the carrier mobility is 10 cm ² / V · sec or more, and the carrier density is 1 × 10 ¹⁹ cm ⁻³ or more. The transparent conductive film forming method according to claim 1, wherein the transparent conductive film is formed.
(Claim 19)
The method for forming a transparent conductive film according to claim 1, wherein the carbon content of the transparent conductive film is 2 to 0.01 atomic%.
(Claim 20)
The method for forming a transparent conductive film according to claim 1, wherein the transparent conductive film has a nitrogen content of 2 to 0.01 atomic%.
(Claim 21)
The transparent conductive film is any one of indium oxide, tin oxide, zinc oxide, fluorine-doped tin oxide, Al-doped zinc oxide, Sb-doped tin oxide, ITO, and an In ₂ O ₃ —ZnO-based amorphous transparent conductive film. The method for forming a transparent conductive film according to claim 1, wherein the transparent conductive film is formed.
(Claim 22)
The transparent conductive film forming method according to any one of claims 1 to 21, wherein the base material on which the transparent conductive film is formed is a transparent resin film or glass.

  According to the present invention, it was possible to provide a method for forming a transparent conductive film capable of achieving high-density plasma and forming a high-quality transparent conductive film using an inexpensive discharge gas mainly composed of nitrogen gas. .

  Next, the best mode for carrying out the present invention will be described, but the present invention is not limited thereto.

  Hereinafter, the present invention will be described in detail.

  In the present invention, the term “transparent conductive film” is a term generally used in the field of industrial materials, and in the present invention, it is used in the meaning of a term generally used in the field of industrial materials. .

  The transparent conductive film is a transparent film that absorbs little light in the visible light (400 to 700 nm) region, is transparent, and has conductivity. It is used as a transparent electrode or an antistatic film because the transmission characteristics of a free charged substance carrying electricity is high in the visible light range, is transparent, and has high electrical conductivity.

  In the present invention, the transparent conductive film only needs to be formed on the object to be processed to such an extent that the transparent conductive film has its function, and even if it is continuously formed on all or part of the object to be processed, , May be formed discontinuously.

As the transparent conductive film, a metal thin film such as Pt, Au, Ag, or Cu, SnO ₂ , In ₂ O ₃ , CdO, ZnO ₂ , SnO ₂ : Sb, SnO ₂ : F, ZnO: Al, In ₂ O ₃ : Examples thereof include oxide films such as Sn, composite oxide films using these oxides and dopants, and non-oxide films such as chalcogenides, LaB ₆ , TiN, and TiC.

  The transparent conductive film forming method of the present invention is carried out by so-called atmospheric pressure plasma CVD method. Hereinafter, the atmospheric pressure plasma CVD method will be described.

  In the present invention, the discharge treatment by the atmospheric pressure plasma CVD method is performed under atmospheric pressure or a pressure in the vicinity thereof, and the atmospheric pressure or the pressure in the vicinity thereof is about 20 kPa to 110 kPa, which is preferable according to the present invention. In order to obtain an effect, 93 kPa to 104 kPa is preferable.

  In the transparent conductive film forming method of the present invention, the gas supplied between the counter electrodes is at least a discharge gas excited by an electric field, and a transparent conductive film that receives the energy and forms a transparent conductive film in a plasma state or an excited state. Contains forming gas.

  In a specific example of a transparent conductive film forming method according to a conventional technique, for example, an atmospheric pressure plasma discharge processing method disclosed in WO02 / 48428 (PCT / JP01 / 10666) or the like, a rare gas such as helium or argon is used. Was used as a discharge gas, and a transparent conductive film was formed by applying a high-frequency electric field exceeding 100 kHz and up to about 150 MHz, preferably about several hundred kHz to 100 MHz. By applying such a high-frequency electric field, a dense and uniform thin film can be obtained, and the productivity of forming a transparent conductive film is excellent. In this case, the high frequency voltage (interelectrode voltage) was sufficient to start the discharge of helium gas or argon gas.

  However, in the above-described transparent conductive film forming method, with a rare gas discharge gas such as helium or argon, the production cost when forming the transparent conductive film often depends on the cost of the discharge gas, and from an environmental standpoint. However, the present inventors have examined the use of an alternative discharge gas. As a result of investigating air, oxygen, nitrogen, carbon dioxide, hydrogen, etc. as alternative discharge gases, the conditions for discharging with these gases are also found, and the formation of a transparent conductive film is excellent, and the formed thin film is dense and uniform. As a result of studying the following conditions and methods, the present invention has been achieved.

  The discharge gas is a gas capable of causing glow discharge capable of forming a thin film. Examples of the discharge gas include nitrogen, rare gas, air, hydrogen gas, oxygen, and the like. These may be used alone as a discharge gas or may be mixed. In the present invention, nitrogen is preferred as the discharge gas. 50-100 volume% of discharge gas contains nitrogen gas. At this time, as the discharge gas other than nitrogen, it is preferable to contain a rare gas of less than 50% by volume. Moreover, it is preferable to contain 90-99.9 volume% of quantity of discharge gas with respect to the total gas quantity supplied to discharge space.

  The reactive gas includes a thin film forming gas and an additive gas, and the thin film forming gas is a raw material that is excited and activated by itself and is chemically deposited on the substrate to form a thin film.

  The supplied gas contains at least a discharge gas and a thin film forming gas. The discharge gas and the thin film forming gas may be mixed and supplied, or may be supplied separately.

  Examples of the thin film forming gas for forming the transparent conductive film used in the present invention include organometallic compounds, halogen metal compounds, and metal hydrogen compounds described later. The thin film forming gas contains at least one additive gas selected from these organometallic compounds, metal halides, and metal hydrides.

  In carrying out the method for forming a transparent conductive film of the present invention, a reactive gas to be used (reactive gas is in a plasma state in a discharge space and forms a conductive film) is added in addition to the thin film film forming gas. As the gas component, an inorganic gas having at least one oxygen atom in the molecule is used.

  Examples of the inorganic gas having at least one oxygen atom in the molecule used in the present invention include oxygen, carbon dioxide, carbon monoxide, dinitrogen monoxide, nitrogen dioxide, sulfur monoxide, sulfur dioxide, ozone and the like. Preferred inorganic gases are nitrogen dioxide and oxygen, and particularly preferred inorganic gas is nitrogen dioxide. These gases can be used in the range of 0.0001 to 5.0% by volume with respect to the mixed gas forming the reactive gas, but the preferred range is 0.001 to 3.0% by volume.

  By using a mixture of these inorganic gases containing oxygen atoms, the disadvantage of easily containing contaminants (impurities) such as carbon and nitrogen in the film when nitrogen gas is used as the discharge gas is improved. it is conceivable that. By using an inorganic gas containing oxygen atoms together with nitrogen gas, contamination such as carbon and nitrogen is reduced, so components derived from mixed carbon and nitrogen trap carriers in the film, and carrier density and mobility. The disadvantage of reducing the degree and increasing the resistivity is thought to be improved.

  Further, in the present invention, in order to further improve the characteristics of the conductive film, a mixture gas containing the discharge gas and the reactive gas is applied between the electrodes to which the high frequency electric field is applied and between the electrodes to which the high frequency electric field is applied. The atmosphere should be inert so that the oxygen concentration in the atmosphere around the discharge space (outside the discharge space) including the space where the generated plasma comes into contact with the substrate is 5% by volume or less. Is preferred.

  If there is too much active gas having an oxygen concentration of 5% by volume or more around the discharge space, it is taken in from the periphery of the discharge space and turned into plasma, so that oxygen in the formed transparent conductive film, carbon Since the concentration increases and the conductivity decreases, the oxidizing gas, particularly oxygen gas, should be suppressed to 5% by volume or less outside the discharge space.

  Accordingly, the oxygen is reduced to 5% by volume or less in the space between the electrode and between the electrodes and the space where the plasma collides with the substrate and forms a thin film on the substrate and in the vicinity thereof (discharge space). This may be supplied by blowing air or inert gas. As oxygen concentration, 3 mass% or less is preferable, and also it is preferable not to contain substantially.

  As the inert gas used, any one or more selected from the group consisting of nitrogen, argon, helium, neon, and xenon may be used. Nitrogen is preferred. Alternatively, a gas obtained by diluting air with the inert gas such as nitrogen or argon so that the oxygen concentration is 5% or less may be used.

  By supplying a gas having a reduced or no oxygen concentration around the plasma generation space, an air curtain can be formed and the influence of oxygen from the outside air can be blocked.

  An example of an apparatus related to these methods is shown in FIG.

  In addition to simply purging (blowing) an inert gas around the discharge space, for example, as disclosed in JP-A-2002-155371, the discharge space is separated from the surroundings, and the reactive property is contained in the discharge space. An apparatus in which a space in which an inert gas atmosphere with an oxygen concentration of 5% by volume or less is provided around the gas and the discharge gas so as to surround the discharge space is also preferable.

  An example of this device is also shown in FIG.

  Next, a specific method for performing the plasma treatment will be described.

In the atmospheric pressure plasma CVD method using nitrogen as a discharge gas according to the present invention, the reactive gas is introduced between the electrodes, a high frequency electric field is applied, plasma is generated, and the substrate is reacted in the plasma state. Although it is performed by exposing to a gas, a gas such as nitrogen has a high electric field strength (hereinafter also referred to as electric field strength) for starting discharge, and a stable discharge cannot be obtained under a conventional high-frequency electric field. As a discharge condition, a component obtained by superimposing a voltage component of the first frequency ω _{1 and} a voltage component of the second frequency ω ₂ higher than the first frequency ω _{1 in} the discharge space between the opposing electrodes. It is preferable to apply at least the first high-frequency electric field and the second high-frequency electric field generated by these two high-frequency potentials as the high-frequency electric field, and apply the first high-frequency electric field (frequency ω ₁ ) Strength V ₁ , second high-frequency electric field (frequency ω ₂ ) strength V _2, and discharge start electric field strength IV are
V ₁ ≧ IV> V ₂
Or satisfies the V _1> IV ≧ V ₂ is preferred.

  High frequency refers to one having a frequency of at least 0.5 kHz.

High frequency electric field to be superimposed, if are both sine wave becomes a first high-frequency electric field of a frequency omega ₁ and the frequency omega higher than ₁ second high-frequency electric field of a frequency omega ₂ and the superposed component, its waveform frequency A sine wave having a higher frequency ω ₂ is superimposed on the sine wave of ω ₁ , resulting in a sawtooth waveform.

  In the present invention, the strength of the electric field at which discharge starts is the lowest electric field intensity that can cause discharge in the discharge space (such as electrode configuration) and reaction conditions (such as gas conditions) used in the actual thin film formation method. Point to. The discharge start electric field strength varies somewhat depending on the type of gas supplied to the discharge space, the dielectric type of the electrode, or the distance between the electrodes, but is controlled by the discharge start electric field strength of the discharge gas in the same discharge space.

By applying a high-frequency electric field as described above to the discharge space, it is presumed that a discharge capable of forming a thin film is generated and high-density plasma necessary for forming a high-quality thin film can be generated.
What is important here is that such a high-frequency electric field is applied to the opposing electrodes, that is, applied to the same discharge space. As described in Japanese Patent Application Laid-Open No. 11-16696, the thin film formation of the present invention cannot be achieved by a method in which two application electrodes are juxtaposed and different high-frequency electric fields are applied to the different discharge spaces.

  Although the superposition of continuous waves such as sine waves has been described above, the present invention is not limited to this, and both pulse waves may be used, one of them may be a continuous wave and the other may be a pulse wave. Further, it may have a third electric field.

As a specific method for applying the high-frequency electric field of the present invention to the same discharge space, a first high-frequency electric field having a frequency ω ₁ and an electric field strength V ₁ is applied to the first electrode constituting the counter electrode. An atmospheric pressure plasma discharge treatment apparatus is used in which a first power source is connected, and a second power source is connected to the second electrode to apply a second high-frequency electric field having a frequency ω ₂ and an electric field strength V ₂ .

  The atmospheric pressure plasma discharge treatment apparatus includes a gas supply unit that supplies a discharge gas and a thin film forming gas between the counter electrodes. Furthermore, it is preferable to have an electrode temperature control means for controlling the temperature of the electrode.

  Further, it is preferable to connect the first filter to the first electrode, the first power source or any of them, and connect the second filter to the second electrode, the second power source or any of them, The first filter facilitates the passage of the first high-frequency electric field current from the first power source to the first electrode, grounds the second high-frequency electric field current, and the second filter from the second power source to the first power source. It makes it difficult to pass the current of the high frequency electric field. On the other hand, the second filter makes it easy to pass the current of the second high-frequency electric field from the second power source to the second electrode, grounds the current of the first high-frequency electric field, and the second power from the first power source. A power supply having a function of making it difficult to pass the current of the first high-frequency electric field to the power supply is used. Here, being difficult to pass means that it preferably passes only 20% or less of the current, more preferably 10% or less. On the contrary, being easy to pass means preferably passing 80% or more of the current, more preferably 90% or more.

  Furthermore, it is preferable that the first power source of the atmospheric pressure plasma discharge processing apparatus of the present invention has a capability of applying a higher frequency electric field strength than the second power source.

  Here, the high frequency electric field strength (applied electric field strength) and the discharge starting electric field strength referred to in the present invention are those measured by the following method.

Measuring method of high-frequency electric field strengths V ₁ and V ₂ (unit: kV / mm):
A high-frequency voltage probe (P6015A) is installed in each electrode section, and the output signal of the high-frequency voltage probe is connected to an oscilloscope (Tektronix, TDS3012B), and the electric field strength is measured.

Measuring method of electric discharge starting electric field intensity IV (unit: kV / mm):
A discharge gas is supplied between the electrodes, the electric field strength between the electrodes is increased, and the electric field strength at which discharge starts is defined as a discharge starting electric field strength IV. The measuring instrument is the same as the high frequency electric field strength measurement.

  The positional relationship between the high-frequency voltage probe used for the measurement and the oscilloscope is shown in FIG.

  By adopting the discharge conditions of the present invention, even a discharge gas having a high discharge starting electric field strength, such as nitrogen gas, can start discharge, maintain a high density and stable plasma state, and form a high-performance thin film. Is possible.

When the discharge gas is nitrogen gas by the above measurement, the discharge start electric field strength IV (1/2 Vp-p) is about 3.7 kV / mm. Therefore, in the above relationship, the first high frequency electric field strength is By applying V ₁ ≧ 3.7 kV / mm, the nitrogen gas can be excited to be in a plasma state.

  Here, the frequency of the first power source is preferably 200 kHz or less. The electric field waveform may be a continuous wave or a pulse wave. The lower limit is preferably about 1 kHz.

  On the other hand, the frequency of the second power source is preferably 800 kHz or more. The higher the frequency of the second power source, the higher the plasma density, and a dense and high-quality thin film can be obtained. The upper limit is preferably about 200 MHz.

  The application of a high frequency electric field from such two power sources is necessary to start the discharge of a discharge gas having a high discharge start electric field strength by the first high frequency electric field, and the high frequency of the second high frequency electric field. In addition, it is an important point of the present invention to form a dense and high-quality thin film by increasing the plasma density with a high power density.

  Also, by increasing the output density of the first high-frequency electric field, the output density of the second high-frequency electric field can be improved while maintaining the uniformity of discharge. Thereby, a further uniform high-density plasma can be generated, and a further improvement in film formation speed and an improvement in film quality can be achieved.

  In the atmospheric pressure plasma discharge processing apparatus used in the present invention, the first filter facilitates passage of the current of the first high-frequency electric field from the first power source to the first electrode, and grounds the current of the second high-frequency electric field. Thus, it is difficult to pass the current of the second high-frequency electric field from the second power source to the first power source. On the other hand, the second filter makes it easy to pass the current of the first high-frequency electric field from the second power source to the second electrode, grounds the current of the first high-frequency electric field, and the second power source from the first power source. It is difficult to pass the current of the first high-frequency electric field to. In the present invention, any filter having such properties can be used without limitation.

  For example, as the first filter, a capacitor of several tens of pF to several tens of thousands of pF or a coil of about several μH can be used depending on the frequency of the second power source. As the second filter, a coil of 10 μH or more is used according to the frequency of the first power supply, and it can be used as a filter by grounding through these coils or capacitors.

  As described above, the atmospheric pressure plasma discharge treatment apparatus used in the present invention discharges between the counter electrodes, puts the gas introduced between the counter electrodes into a plasma state, and places the gas between the counter electrodes or between the electrodes. By exposing the substrate to be transferred to the plasma state gas, a thin film is formed on the substrate.

In the discharge space where the plasma formed between the counter electrodes is generated, as described above, the gas composition in the discharge space changes due to the influence of the gas (for example, air) from the external space, and In order not to change the characteristics of the transparent conductive film deposited on the material,
The vicinity of the discharge space is treated in an inert gas atmosphere (an inert gas having an oxygen concentration of 5% by mass or less). For this purpose, the discharge device, particularly the discharge vessel, may be placed in an inert gas atmosphere having an oxygen concentration of 5% by volume or less, and the components constituting the transparent conductive film are deposited on the substrate by contacting the substrate with the plasma. An air curtain is formed by blowing an inert gas (an inert gas having an oxygen concentration of 5% by mass or less) so as to surround the discharge space in the vicinity of the discharge space including the space, and the air curtain is activated from the outside. Try to prevent gas ingress.

  Further, the discharge space including the space where the substrate and the plasma come into contact with each other and the components constituting the transparent conductive film are deposited on the substrate is actually covered and surrounded by an inert gas (oxygen). The structure around the discharge space, such as a zone filled with an inert gas having a concentration of 5% by mass or less, may be efficiently cut off from the outside air (ambient) (FIG. 2 described later). ).

  As another method of the atmospheric pressure plasma discharge treatment apparatus, a discharge is made between the counter electrodes similar to the above, the gas introduced between the counter electrodes is excited or put into a plasma state, and the excitation is performed in a jet form outside the counter electrode. Alternatively, a jet-type gas can be formed by blowing a gas in a plasma state and exposing a substrate in the vicinity of the counter electrode (which may be stationary or transferred) to the substrate. There is a device.

  Also in this case, an inert gas is introduced in the vicinity so as to block the discharge space similar to the above from the outside air.

  FIG. 1 is a schematic view showing an example of a jet type atmospheric pressure plasma discharge treatment apparatus useful for the present invention.

  In addition to the plasma discharge processing apparatus and the electric field applying means having two power sources, the jet type atmospheric pressure plasma discharge processing apparatus is not shown in FIG. And an electrode temperature adjusting means.

The plasma discharge processing apparatus 10 has a counter electrode composed of a first electrode 11 and a second electrode 12, and the frequency ω ₁ from the first power supply 21 is output from the first electrode 11 between the counter electrodes. A first high frequency electric field having electric field strength V ₁ and current I ₁ is applied, and a second high frequency electric field having frequency ω ₂ , electric field strength V ₂ and current I ₂ from second power source 22 is applied from second electrode 12. Is applied. The first power source 21 can apply a higher frequency electric field strength (V ₁ > V ₂ ) than the second power source 22, and the first frequency ω ₁ of the first power source 21 is higher than the second frequency ω ₂ of the second power source 22. A low frequency can be applied.

  A first filter 23 is installed between the first electrode 11 and the first power source 21 to facilitate passage of current from the first power source 21 to the first electrode 11, and current from the second power source 22. Is designed so that the current from the second power source 22 to the first power source 21 is less likely to pass through.

  In addition, a second filter 24 is installed between the second electrode 12 and the second power source 22 to facilitate passage of current from the second power source 22 to the second electrode, and from the first power source 21. It is designed to ground the current and make it difficult to pass the current from the first power source 21 to the second power source.

  A gas G is introduced into a gap 13 between the first electrode 11 and the second electrode 12 from a gas supply means as illustrated in FIG. 3 to be described later, and a high-frequency electric field is transmitted from the first electrode 11 and the second electrode 12. Is generated by discharging the gas G from the gas blowing port 8 to the lower side (the lower side of the drawing) of the counter electrode while making the gas G into a plasma state. The processing space is filled with plasma gas G °, and is unwound from a base roll (unwinder) (not shown) and conveyed, or on the substrate F conveyed from the previous step. A thin film is formed in the vicinity of the outlet 14.

  During the thin film formation, the medium heats or cools the electrode through the pipe from the electrode temperature adjusting means as shown in FIG. Depending on the temperature of the base material during the plasma discharge treatment, the properties, composition, etc. of the thin film obtained may change, and it is desirable to appropriately control this. As the temperature control medium, an insulating material such as distilled water or oil is preferably used. During the plasma discharge treatment, it is desirable to uniformly adjust the temperature inside the electrode so that the temperature unevenness of the base material in the width direction or the longitudinal direction does not occur as much as possible.

  FIG. 1 shows a measuring instrument used for measuring the above-described high-frequency electric field strength (applied electric field strength) and discharge starting electric field strength. Reference numerals 25 and 26 are high-frequency voltage probes, and reference numerals 27 and 28 are oscilloscopes.

  The space where the plasma is generated in FIG. 1 including the space between the two electrodes of the first electrode 11 and the second electrode 12 and the space where the thin film is deposited on the substrate when the substrate F is in contact with the plasma is defined as the discharge space. In FIG. 1, an inert gas G ″ containing 5% by volume or less of oxygen is placed on the surface opposite to the discharge surface of the first and second electrodes 11 and 12 (outside) in the discharge space. (For example, the pipe L has a plurality of outlets L in parallel in the depth direction of the paper) to introduce an air curtain. The arrows indicate the flow of the introduced gas G ″. This inert gas (5% by volume or less oxygen) causes the active gas such as oxygen having a great influence on the properties of the thin film formed from the outside air to be excessively mixed in the plasma and deteriorate the properties of the thin film. To prevent. In addition, it has a similar inert gas supply pipe that shuts off the discharge space from the external atmosphere by the flow of inert gas at both ends in the depth direction (width direction of the treatment substrate) as viewed from the paper surface of the electrode, It is omitted in the figure.

  FIG. 2A shows another example of the plasma discharge processing apparatus according to the present invention.

  In FIG. 2 (a), an exhaust gas cylinder 5 provided with a gas escape port 2 is provided so as to cover the flow of the reactive gas G, and the reactive gas G introduced from the inlet port becomes a plasma state between the electrodes. After processing the base material F, it becomes exhaust gas G ′ and is collected through the exhaust gas cylinder 5 as indicated by an arrow. Further, there is a spare chamber filled with an inert gas from the gas supply port provided with another gas supply port 3 for supplying another inert gas G ″ outside the exhaust gas cylinder 5. ″ Is blown against the substrate surface through a plurality of holes (inert gas blowing ports) 4 provided on the substrate side of the preliminary chamber to form an air curtain, thereby containing an active gas such as oxygen. The discharge space is blocked from the external atmosphere, and a thin film can be formed. The inert gas G ″ introduced from the inert gas inlet 3 and blown out from the plurality of holes (inert gas outlets) 4 of the preliminary chamber is exhausted through the exhaust gas cylinder 6.

  FIG. 2B is a view of the apparatus of FIG. 2A viewed from the substrate surface side. The gas blowing port 14, a plurality of inert gas blowing ports 4 formed in the preliminary chamber substrate surface, and the exhaust gas cylinder are shown. 5 and 6 openings are shown.

  The processing apparatus shown in FIG. 2 (a) or 2 (b) is merely an example, and any form may be used as long as it basically has such a function.

  A plurality of such jet-type atmospheric pressure plasma discharge treatment apparatuses can be connected in series and discharged in the same plasma state at the same time, and can be processed at high speed.

  FIG. 3 is a schematic view showing an example of an atmospheric pressure plasma discharge treatment apparatus that treats a substrate between opposed electrodes.

  The atmospheric pressure plasma discharge treatment apparatus of the present invention is an apparatus having at least a plasma discharge treatment apparatus 30, an electric field application means 40 having two power supplies, a gas supply means 50, and an electrode temperature adjustment means 60.

  FIG. 3 shows a thin film formed by subjecting the base material F to plasma discharge treatment between the opposed electrodes (discharge space) 32 between the roll rotating electrode (first electrode) 35 and the square tube type fixed electrode group (second electrode) 36. To do.

In the discharge space (between the counter electrodes) 32 between the roll rotating electrode (first electrode) 35 and the square tube type fixed electrode group (second electrode) 36, the roll rotating electrode (first electrode) 35 has a first power source. The first high-frequency electric field having frequency ω ₁ , electric field strength V ₁ and current I ₁ from 41, and the frequency ω ₂ and electric field strength V ₂ from the second power source 42 to the square tube fixed electrode group (second electrode) 36. A second high-frequency electric field of current I ₂ is applied.

  A first filter 43 is installed between the roll rotation electrode (first electrode) 35 and the first power supply 41, and the first filter 43 easily passes a current from the first power supply 41 to the first electrode. The current from the second power supply 42 is grounded so that the current from the second power supply 42 to the first power supply is difficult to pass. Further, a second filter 44 is provided between the square tube type fixed electrode group (second electrode) 36 and the second power source 42, and the second filter 44 is connected from the second power source 42 to the second electrode. It is designed so that the current from the first power supply 41 is grounded and the current from the first power supply 41 to the second power supply is difficult to pass.

In the present invention, the roll rotation electrode 35 may be the second electrode, and the rectangular tube-shaped fixed electrode group 36 may be the first electrode. In any case, the first power source is connected to the first electrode, and the second power source is connected to the second electrode. The first power supply preferably applies a higher frequency electric field strength (V ₁ > V ₂ ) than the second power supply. Further, the frequency has the ability to satisfy ω ₁ <ω ₂ .
The current is preferably I ₁ <I ₂ . Current I ₁ of the first high-frequency electric field is preferably ^{0.3mA / cm 2 ~20mA / cm 2} , more preferably at ^{1.0mA / cm 2 ~20mA / cm 2} . The current I ₂ of the second high-frequency electric field is preferably ^{10mA / cm 2 ~100mA / cm 2} , more preferably ^{20mA / cm 2 ~100mA / cm 2} .

  The gas G generated by the gas generator 51 of the gas supply means 50 is introduced into the plasma discharge processing vessel 31 from the air supply port 52 while controlling the flow rate.

  The base material F is unwound from the original winding (not shown) and is transported or is transported from the previous process, and the air and the like that is entrained by the base material by the nip roll 65 through the guide roll 64 is blocked. Then, while being wound while being in contact with the roll rotating electrode 35, it is transferred between the square tube fixed electrode group 36 and the roll rotating electrode (first electrode) 35 and the square tube fixed electrode group (second electrode) 36. An electric field is applied from both of them to generate discharge plasma between the counter electrodes (discharge space) 32. The base material F forms a thin film with a gas in a plasma state while being wound while being in contact with the roll rotating electrode 35. The base material F passes through the nip roll 66 and the guide roll 67 and is wound up by a winder (not shown) or transferred to the next process.

  FIG. 3 shows a measuring instrument used for measuring the above-described high-frequency voltage (applied voltage) and discharge start voltage. Reference numerals 25 and 26 are high-frequency probes, and reference numerals 27 and 28 are oscilloscopes.

  Discharged treated exhaust gas G ′ is discharged from the exhaust port 53.

  In order to heat or cool the roll rotating electrode (first electrode) 35 and the rectangular tube type fixed electrode group (second electrode) 36 during the formation of the thin film, a medium whose temperature is adjusted by the electrode temperature adjusting means 60 is used as a liquid feed pump. P is sent to both electrodes through the pipe 61, and the temperature is adjusted from the inside of the electrode. Reference numerals 68 and 69 denote partition plates that partition the plasma discharge processing vessel 31 from the outside.

  FIG. 4 is a perspective view showing an example of the structure of the conductive metallic base material of the roll rotating electrode shown in FIG. 3 and the dielectric material coated thereon.

  In FIG. 4, a roll electrode 35a is formed by covering a conductive metallic base material 35A and a dielectric 35B thereon. In order to control the electrode surface temperature during the plasma discharge treatment, a temperature adjusting medium (water, silicon oil or the like) can be circulated.

  FIG. 5 is a perspective view showing an example of the structure of a conductive metallic base material of a rectangular tube electrode and a dielectric material coated thereon.

  In FIG. 5, a rectangular tube type electrode 36a has a coating of a dielectric 36B similar to FIG. 4 on a conductive metallic base material 36A, and the structure of the electrode is a metallic pipe. , It becomes a jacket so that the temperature can be adjusted during discharge.

  In addition, the number of the rectangular tube-shaped fixed electrodes is set in plural along the circumference larger than the circumference of the roll electrode, and the discharge area of the electrodes is a full square tube type facing the roll rotating electrode 35. It is represented by the sum of the area of the fixed electrode surface.

  The rectangular tube electrode 36a shown in FIG. 5 may be a cylindrical electrode, but the rectangular tube electrode has an effect of widening the discharge range (discharge area) as compared with the cylindrical electrode, and thus is preferably used in the present invention. .

  4 and 5, a roll electrode 35a and a rectangular tube electrode 36a are formed by spraying ceramics as dielectrics 35B and 36B on conductive metallic base materials 35A and 36A, respectively, and then sealing the inorganic compound sealing material. Used and sealed. The ceramic dielectric may be covered by about 1 mm with a single wall. As the ceramic material used for thermal spraying, alumina, silicon nitride, or the like is preferably used. Among these, alumina is particularly preferable because it is easily processed. The dielectric layer may be a lining-processed dielectric provided with an inorganic material by lining.

  Examples of the conductive metal base materials 35A and 36A include titanium metal or titanium alloy, metal such as silver, platinum, stainless steel, aluminum, and iron, a composite material of iron and ceramics, or a composite material of aluminum and ceramics. Although titanium metal or a titanium alloy is particularly preferable for the reasons described later.

  When the dielectric is provided on one of the electrodes, the distance between the opposing first electrode and second electrode is the shortest distance between the surface of the dielectric and the surface of the conductive metal base material of the other electrode. Say that. When a dielectric is provided on both electrodes, it means the shortest distance between the dielectric surfaces. The distance between the electrodes is determined in consideration of the thickness of the dielectric provided on the conductive metallic base material, the magnitude of the applied electric field strength, the purpose of using the plasma, etc. From the viewpoint of performing 0.15 mm, 0.1 to 20 mm is preferable, and 0.5 to 2 mm is particularly preferable.

  Details of the conductive metallic base material and dielectric useful in the present invention will be described later.

  The plasma discharge treatment vessel 31 is preferably a treatment vessel made of Pyrex (R) glass or the like, but can be made of metal as long as it can be insulated from the electrodes.

  For example, polyimide resin or the like may be attached to the inner surface of an aluminum or stainless steel frame, and the metal frame may be thermally sprayed to obtain insulation.

  Since the gas in the external atmosphere tends to flow into the plasma discharge treatment vessel 31 particularly on both side surfaces of both parallel electrodes, although not shown in FIG. It is preferable to provide a cover that covers up to near the base material surface with a simple material. FIGS. 6A and 6B show an example in which a cover 31A is provided on the side surface of the plasma discharge processing container so that the electrode side surface can be shielded from the external atmosphere. Although not shown in FIG. 3, both sides of the electrode of the plasma discharge treatment vessel 31 are covered with a cover 31A, and as shown in FIG. An active gas G ″ (oxygen 5 vol% or less) is supplied (supply path is omitted) to prevent the external atmosphere from entering the plasma processing space. 31B is provided at the end of the plasma discharge processing vessel. This is an inert gas supply port, whereby the periphery of the plasma processing space is shielded from the external atmosphere by the inert gas.

As the first power source (high frequency power source) installed in the atmospheric pressure plasma discharge processing apparatus of the present invention,
Applied power symbol Manufacturer Frequency Product name A1 Shinko Electric 3kHz SPG3-4500
A2 Shinko Electric 5kHz SPG5-4500
A3 Kasuga Electric 15kHz AGI-023
A4 Shinko Electric 50kHz SPG50-4500
A5 HEIDEN Research Laboratories 100kHz * PHF-6k
A6 Pearl Industry 200kHz CF-2000-200k
A7 Pearl Industry 400kHz CF-2000-400k
And the like, and any of them can be used.

As the second power source (high frequency power source),
Applied power supply symbol Manufacturer Frequency Product name B1 Pearl Industry 800kHz CF-2000-800k
B2 Pearl Industry 2MHz CF-2000-2M
B3 Pearl Industry 13.56MHz CF-5000-13M
B4 Pearl Industry 27MHz CF-2000-27M
B5 Pearl Industry 150MHz CF-2000-150M
And the like, and any of them can be preferably used.
Of the above power supplies, * indicates a HEIDEN Laboratory impulse high-frequency power supply (100 kHz in continuous mode). Other than that, it is a high-frequency power source that can apply only a continuous sine wave.

  In the present invention, it is preferable to employ an electrode capable of maintaining a uniform and stable discharge state by applying such an electric field in an atmospheric pressure plasma discharge treatment apparatus.

In the present invention, the electric power applied between the electrodes facing each other supplies power (power density) of 1 W / cm ² or more to the second electrode (second high-frequency electric field) to excite the discharge gas to generate plasma. The energy is applied to the thin film forming gas to form a thin film. The upper limit value of the power supplied to the second electrode is preferably 50 W / cm ² , more preferably 20 W / cm ² . The lower limit is preferably 1W / cm ^2, more preferably 1.2 W / cm ^2. The discharge area (cm ² ) refers to an area in a range where discharge occurs in the electrode.

Further, by supplying power (output density) of 1 W / cm ² or more to the first electrode (first high frequency electric field), the output density is improved while maintaining the uniformity of the second high frequency electric field. I can do it. Thereby, a further uniform high-density plasma can be generated, and a further improvement in film forming speed and an improvement in film quality can be achieved. Preferably it is 5 W / cm ² or more. The upper limit value of the power supplied to the first electrode is preferably 50 W / cm ² .

  Here, the waveform of the high-frequency electric field is not particularly limited. There are a continuous sine wave continuous oscillation mode called a continuous mode, an intermittent oscillation mode called ON / OFF intermittently called a pulse mode, and either of them may be adopted, but at least the second electrode side (second The high-frequency electric field is preferably a continuous sine wave because a denser and better quality film can be obtained.

  An electrode used in such a method for forming a thin film by atmospheric pressure plasma must be able to withstand severe conditions in terms of structure and performance. Such an electrode is preferably a metal base material coated with a dielectric.

In the dielectric-coated electrode used in the present invention, it is preferable that the characteristics match between various metallic base materials and dielectrics. One of the characteristics is linear thermal expansion between the metallic base material and the dielectric. The combination is such that the difference in coefficient is 10 × 10 ⁻⁶ / ° C. or less. It is preferably 8 × 10 ⁻⁶ / ° C. or less, more preferably 5 × 10 ⁻⁶ / ° C. or less, and further preferably 2 × 10 ⁻⁶ / ° C. or less. The linear thermal expansion coefficient is a well-known physical property value of a material.

As a combination of a conductive metallic base material and a dielectric whose difference in linear thermal expansion coefficient is within this range,
1. 1. Metal base material is pure titanium or titanium alloy, and dielectric is ceramic spray coating. 2. Metal base material is pure titanium or titanium alloy, and dielectric is glass lining. 3. Metal base material is stainless steel and dielectric is ceramic sprayed coating. 4. Metal base material is stainless steel and dielectric is glass lining. 5. The metal base material is a composite material of ceramics and iron, and the dielectric is a ceramic spray coating. 6. Metal base material is a composite material of ceramics and iron, and dielectric is glass lining 7. The metal base material is a composite material of ceramics and aluminum, and the dielectric is a ceramic spray coating. The metal base material is a composite material of ceramics and aluminum, and the dielectric is glass lining. From the viewpoint of the difference in coefficient of linear thermal expansion, the above 1. Or 2. And 5. ~ 8. In particular, Is preferred.

  In the present invention, titanium or a titanium alloy is particularly useful as the metallic base material from the above characteristics. By using titanium or a titanium alloy as the metal base material, the dielectric is used as described above, so that there is no deterioration of the electrode in use, especially cracking, peeling, dropping off, etc., and it can be used for a long time under harsh conditions. Can withstand.

  The metallic base material of the electrode useful in the present invention is a titanium alloy or titanium metal containing 70% by mass or more of titanium. In the present invention, if the titanium content in the titanium alloy or titanium metal is 70% by mass or more, it can be used without any problem, but preferably contains 80% by mass or more of titanium. As the titanium alloy or titanium metal useful in the present invention, those generally used as industrial pure titanium, corrosion resistant titanium, high strength titanium and the like can be used. Examples of pure titanium for industrial use include TIA, TIB, TIC, TID, etc., all of which contain very little iron atom, carbon atom, nitrogen atom, oxygen atom, hydrogen atom, etc. As content, it has 99 mass% or more. As the corrosion-resistant titanium alloy, T15PB can be preferably used, and it contains lead in addition to the above-mentioned atoms, and the titanium content is 98% by mass or more. Further, as the titanium alloy, T64, T325, T525, TA3, etc. containing aluminum and vanadium or tin in addition to the above atoms except lead can be preferably used. As a quantity, it contains 85 mass% or more. These titanium alloys or titanium metals have a thermal expansion coefficient that is about 1/2 smaller than that of stainless steel, such as AISI 316, and are combined with a dielectric described later applied on the titanium alloy or titanium metal as a metallic base material. It can withstand the use at high temperature for a long time.

  On the other hand, as a required characteristic of the dielectric, specifically, an inorganic compound having a relative dielectric constant of 6 to 45 is preferable, and examples of such a dielectric include ceramics such as alumina and silicon nitride, Alternatively, there are glass lining materials such as silicate glass and borate glass. In this, what sprayed the ceramics mentioned later and the thing provided by glass lining are preferable. In particular, a dielectric provided by spraying alumina is preferable.

  Alternatively, as one of the specifications that can withstand high power as described above, the porosity of the dielectric is 10% by volume or less, preferably 8% by volume or less, preferably more than 0% by volume and 5% by volume or less. It is. The porosity of the dielectric can be measured by a BET adsorption method or a mercury porosimeter. In the examples described later, the porosity is measured using a dielectric fragment covered with a metallic base material by a mercury porosimeter manufactured by Shimadzu Corporation. High durability is achieved because the dielectric has a low porosity. Examples of the dielectric having such a void and a low void ratio include a high-density, high-adhesion ceramic spray coating by an atmospheric plasma spraying method described later. In order to further reduce the porosity, it is preferable to perform sealing treatment.

  The above-mentioned atmospheric plasma spraying method is a technique in which fine powder such as ceramics, wire, or the like is put into a plasma heat source and sprayed onto a metallic base material to be coated as fine particles in a molten or semi-molten state to form a film. A plasma heat source is a high-temperature plasma gas in which a molecular gas is heated to a high temperature, dissociated into atoms, and further given energy to release electrons. The plasma gas injection speed is high, and since the sprayed material collides with the metallic base material at a higher speed than conventional arc spraying or flame spraying, high adhesion strength and high density coating can be obtained. Specifically, reference can be made to a thermal spraying method for forming a heat shielding film on a high-temperature exposed member described in JP-A-2000-301655. By this method, the porosity of the dielectric (ceramic sprayed film) to be coated can be obtained.

  Another preferable specification that can withstand high power is that the dielectric thickness is 0.5 to 2 mm. The film thickness variation is desirably 5% or less, preferably 3% or less, and more preferably 1% or less.

In order to further reduce the porosity of the dielectric, it is preferable to further perform a sealing treatment with an inorganic compound on the sprayed film such as ceramics as described above. As the inorganic compound, a metal oxide is preferable, and among these, a compound containing silicon oxide (SiO _x ) as a main component is particularly preferable.

  The inorganic compound for sealing treatment is preferably formed by curing by a sol-gel reaction. In the case where the inorganic compound for sealing treatment contains a metal oxide as a main component, a metal alkoxide or the like is applied as a sealing liquid on the ceramic sprayed film and cured by a sol-gel reaction. When the inorganic compound is mainly composed of silica, it is preferable to use alkoxysilane as the sealing liquid.

  Here, it is preferable to use energy treatment for promoting the sol-gel reaction. Examples of the energy treatment include thermal curing (preferably 200 ° C. or less) and ultraviolet irradiation. Further, when the sealing liquid is diluted as the method of sealing treatment and coating and curing are repeated several times in succession, the mineralization is further improved and a dense electrode without deterioration can be obtained.

In the case of performing a sealing treatment that cures by a sol-gel reaction after coating a ceramic sprayed film using the metal alkoxide or the like of the dielectric-coated electrode according to the present invention as a sealing liquid, the content of the metal oxide after curing is 60 It is preferably at least mol%. When alkoxysilane is used as the metal alkoxide of the sealing liquid, the content of SiO _x (x is 2 or less) after curing is preferably 60 mol% or more. The cured SiO _x content is measured by analyzing a tomographic layer of the dielectric layer by XPS (X-ray photoelectron spectroscopy).

  In the electrode according to the thin film forming method of the present invention, the maximum height (Rmax) of the surface roughness defined by JIS B 0601 on the side in contact with at least the substrate of the electrode is adjusted to be 10 μm or less. Although it is preferable from the viewpoint of obtaining the effects described in the present invention, the maximum value of the surface roughness is more preferably 8 μm or less, and particularly preferably 7 μm or less. In this way, the dielectric surface of the dielectric-coated electrode can be polished and the dielectric thickness and the gap between the electrodes can be kept constant, the discharge state can be stabilized, the heat shrinkage difference and Distortion and cracking due to residual stress can be eliminated, and durability can be greatly improved with high accuracy. The polishing finish of the dielectric surface is preferably performed at least on the dielectric in contact with the substrate. Furthermore, the centerline average surface roughness (Ra) defined by JIS B 0601 is preferably 0.5 μm or less, more preferably 0.1 μm or less.

  In the dielectric-coated electrode used in the present invention, another preferred specification that can withstand high power is that the heat-resistant temperature is 100 ° C. or higher. More preferably, it is 120 degreeC or more, Most preferably, it is 150 degreeC or more. The upper limit is 500 ° C. Note that the heat-resistant temperature refers to the highest temperature that can withstand normal discharge without causing dielectric breakdown at the voltage used in the atmospheric pressure plasma treatment. Such heat-resistant temperature can be applied within the range of the difference between the linear thermal expansion coefficient of the metallic base material and the dielectric material by applying the dielectric material provided by the above-mentioned ceramic spraying or layered glass lining with different bubble mixing amounts. This can be achieved by appropriately combining means for appropriately selecting the materials.

  Next, the reactive gas used for the electrically conductive film formation method of this invention is demonstrated. In carrying out the transparent conductive film forming method of the present invention, the reactive gas used is composed of an inorganic gas having at least one oxygen atom in the molecule and an organometallic compound as a thin film forming gas as reactive gas components, In the present invention, it is used as a mixed gas with an inert gas mainly composed of nitrogen gas.

  The reactive gas becomes a plasma state in the discharge space and forms a conductive film.

  In the present invention, the reactive gas is preferably mixed with an inorganic gas having at least one oxygen atom in the molecule. Examples of this include oxygen, carbon dioxide, carbon monoxide, dinitrogen monoxide, Nitrogen dioxide, sulfur monoxide, sulfur dioxide, ozone and the like can be mentioned, and a particularly preferred inorganic gas is nitrogen dioxide. These gases may be used as a mixed gas mixed with a gas selected from nitrogen, helium, and argon, and a mixed gas of nitrogen dioxide and nitrogen is also preferable.

  These gases can be used in a range of 0.0001 to 5.0% by volume with respect to the mixed gas, but a preferable range is 0.001 to 3.0% by volume.

  The discharge gas is a gas capable of causing a glow discharge capable of forming a thin film, and itself functions as a medium for transferring energy. Examples of the discharge gas include nitrogen, rare gas, air, and the like. These may be used alone as a discharge gas or may be used in combination. In the present invention, nitrogen is preferable as the discharge gas, and 50 to 100% by volume of the discharge gas contains nitrogen gas. Moreover, as discharge gas other than nitrogen, you may contain rare gas less than 50 volume%. Examples of the rare gas include Group 18 elements in the periodic table, specifically, helium, neon, argon, krypton, xenon, radon, and the like. Moreover, it is preferable to contain 90-99.9 volume% of quantity of discharge gas with respect to the total gas quantity supplied to discharge space or process space.

  The transparent conductive film forming gas is a raw material that receives energy from the discharge gas and is excited to become active (plasma state) and is chemically deposited on the substrate to form the transparent conductive film. is there.

  The transparent conductive film forming gas used in the present invention will be described.

  Examples of the transparent conductive film forming gas used in the present invention include organic metal compounds, halogen metal compounds, metal hydrogen compounds, and the like.

  In the present invention, the transparent conductive film-forming gas preferably contains an organometallic compound, and an organometallic compound for doping may be added to the metal oxide formed from the organometallic compound. Organometallic compounds are used.

  The organometallic compounds useful in the present invention are preferably those represented by the following general formula (I).

Formula (I) R ¹ _x MR ² _y R ³ _z
In the formula, M is a metal, R ¹ is an alkyl group, R ² is an alkoxy group, R ³ is a β-diketone coordination group, a β-ketocarboxylic acid ester coordination group, a β-ketocarboxylic acid coordination group, and a ketooxy group (ketooxy group). A coordination group), where the valence of the metal M is m, x + y + z = m, x = 0 to m, or x = 0 to m-1, and y = 0 to m. , Z = 0 to m, and each is 0 or a positive integer. Examples of the alkyl group for R ¹ include a methyl group, an ethyl group, a propyl group, and a butyl group. Examples of the alkoxy group for R ² include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a 3,3,3-trifluoropropoxy group. Further, a hydrogen atom in the alkyl group may be substituted with a fluorine atom. As a group selected from a β-diketone coordination group, a β-ketocarboxylic acid ester coordination group, a β-ketocarboxylic acid coordination group and a ketooxy group (ketooxy coordination group) of R ³ , as a β-diketone coordination group, For example, 2,4-pentanedione (also referred to as acetylacetone or acetoacetone), 1,1,1,5,5,5-hexamethyl-2,4-pentanedione, 2,2,6,6-tetramethyl-3 , 5-heptanedione, 1,1,1-trifluoro-2,4-pentanedione, etc., and β-ketocarboxylic acid ester coordination groups include, for example, acetoacetic acid methyl ester, acetoacetic acid ethyl ester, Examples include acetoacetic acid propyl ester, trimethylacetoacetic acid ethyl, trifluoroacetoacetic acid methyl, and the like, as β-ketocarboxylic acid, Eg to acetoacetate, it can be mentioned trimethyl acetoacetate, and as Ketookishi, for example, acetoxy group (or an acetoxy group), a propionyloxy group, Buchirirokishi group, acryloyloxy group, methacryloyloxy group and the like. The number of carbon atoms of these groups is preferably 18 or less, including the above-mentioned organometallic compounds. Further, as illustrated, it may be linear or branched, or a hydrogen atom substituted with a fluorine atom.

In the present invention, an organometallic compound having a low risk of explosion is preferred from the viewpoint of handling, and an organometallic compound having at least one oxygen in the molecule is preferred. As such, an organometallic compound containing at least one alkoxy group of R ² , a β-diketone coordination group, a β-ketocarboxylic acid ester coordination group, a β-ketocarboxylic acid coordination group and a ketooxy group of R ³ A metal compound having at least one group selected from a group (ketooxy coordination group) is preferred.

  The metal of the organometallic compound that can be used in the present invention is not particularly limited, but indium (In), tin (Sn), zinc (Zn), zirconium (Zr), aluminum (Al), antimony (Sb), gallium ( At least one metal selected from Ga) and germanium (Ge) is preferable, and at least one metal selected from indium, zinc and tin is particularly preferable.

  Among these, the compound represented by the general formula 1 or 2 is particularly preferable.

In General Formulas 1 and 2, M represents In, Sn, Zn, R ₁ and R ₂ each represents an alkyl group, an aryl group, or an alkoxyl group that may have a substituent, and R represents a hydrogen atom or a substituted group. Represents a group, and R may combine with R ₁ and R ₂ to form a ring. R ₃ represents an alkyl group or an aryl group each optionally having a substituent. n1 represents an integer, and n2 represents an integer.

  Specific examples of the ligand that forms the organometallic compound represented by the general formula 1 include the compounds shown below.

  The following diketone compounds are also preferred as the ligand.

  In general formulas 1 and 2, M is preferably indium (In). Among the organic compounds of the present invention, preferred examples include indium hexafluoropentanedionate, indiummethyl (trimethyl) acetylacetate, indium acetylacetonate, indium isoporoxide, indium trifluoropentanedionate, tris (2, 2,6,6-tetramethyl 3,5-heptanedionate) indium, di-n-butylbis (2,4-pentanedionate) tin, di-n-butyldiacetoxytin, di-t-butyldiacetoxy Tin, tetraisopropoxytin, tetrabutoxytin, zinc acetylacetonate, etc. can be mentioned. Of these, indium acetylacetonate, tris (2,2,6,6-tetramethyl 3,5-heptanedionate) indium, zinc acetylacetonate and di-n-butyldiacetoxytin are particularly preferable. These organometallic compounds are generally commercially available. For example, indium acetylacetonate can be easily obtained from Tokyo Chemical Industry Co., Ltd.

  In the present invention, examples of the preferable organometallic compound include indium tris 2,4-pentanedionate (or trisacetoacetonatoindium), indium trishexafluoropentanedionate, methyltrimethylacetoxyindium, triacetoacetate. Oxyindium, triacetooxyindium, diethoxyacetoacetoxyindium, indium triisoporopoxide, diethoxyindium (1,1,1-trifluoropentanedionate), tris (2,2,6,6-tetra Methyl-3,5-heptanedionate) indium, ethoxyindium bisacetomethyl acetate, di (n) butylbis (2,4-pentanedionate) tin, di (n) butyldiacetoxytin, di (t) Butyldia Tookishi tin, tetraisopropoxy tin, tetra (i) butoxy tin, can be mentioned zinc 2,4-pentanedionate, etc., both also preferably used.

  Among them, indium tris 2,4-pentanedionate, tris (2,2,6,6-tetramethyl-3,5-heptanedionate) indium, zinc bis 2,4-pentanedionate, di (n ) Butyldiacetoxytin is preferred. These organometallic compounds are generally commercially available (for example, from Tokyo Chemical Industry Co., Ltd.).

  In the present invention, it is preferable that a mixed gas contains an organic metal compound for doping or a fluorine compound for doping for further enhancing the conductivity of the transparent conductive film formed from the organic metal compound. Examples of the gas for forming a transparent conductive film of an organometallic compound for doping or a fluorine compound for doping include, for example, triisopropoxyaluminum, nickel tris 2,4-pentanedionate, manganese bis-2,4-pentanedionate, boron isopropoxide , Tri (n) butoxyantimony, tri (n) butylantimony, di (n) butyltin bis 2,4-pentanedionate, di (n) butyldiacetoxytin, di (t) butyldiacetoxytin, Tetraisopropoxytin, tetrabutoxytin, tetrabutyltin, zinc 2,4-pentanedionate, dipropoxygermanium, di (n) butyldiacetoxygermanium, germanium tris 2,4-pentanedionate, gallium tris 2,4 -Pentandionate, tripropoxygali Arm, butyl diacetoxy oxy gallium, hexafluoropropylene, eight fluoride cyclobutane can be exemplified tetrafluoromethane like.

The ratio between the organometallic compound necessary for forming the transparent conductive film and the transparent conductive film forming gas for doping differs depending on the type of transparent conductive film to be formed. For example, it can be obtained by doping indium oxide with tin. In the ITO film, it is necessary to adjust the amount of the transparent conductive film forming gas so that the atomic ratio of In: Sn is in the range of 100: 0.1 to 100: 15. Preferably, it is preferable to adjust so that it may become 100: 0.5-100: 10. In a transparent conductive film obtained by doping fluorine into tin oxide (a fluorine-doped tin oxide film is referred to as an FTO film), the obtained FTO film has an Sn: F atomic ratio of 100: 0.01 to 100: 50. It is preferable to adjust the amount ratio of the transparent conductive film forming gas so as to be in the range. In the In ₂ O ₃ —ZnO transparent conductive film, the amount ratio of the transparent conductive film forming gas is preferably adjusted so that the In: Zn atomic ratio is in the range of 100: 50 to 100: 5. Each atomic ratio of In: Sn, Sn: F and In: Zn can be determined by XPS measurement.

In the present invention, the obtained transparent conductive film is, for example, SnO ₂ , In ₂ O ₃ (IO), an oxide film of ZnO, or Sb-doped SnO ₂ , FTO (fluorine-doped SnO ₂ ), Al-doped ZnO, Zn-doped. A composite oxide doped with a dopant such as In, ITO, ATO (Zn-doped SnO ₂ ), AZO (Al-doped ZnO), IZO (In ₂ O ₃ —ZnO-based amorphous film), and the like can be selected. An amorphous film containing at least one as a main component is preferable. Other examples include non-oxide films such as chalcogenide, LaB ₆ , TiN, and TiC, metal films such as Pt, Au, Ag, and Cu, and transparent conductive films such as CdO.

  The gas for forming a transparent conductive film of an organometallic compound is preferably contained in an amount of 0.01 to 10% by volume, more preferably 0.1 to 3% by volume in the total gas.

  The gas used in the present invention is preferably mixed with an inorganic gas having at least one oxygen atom in the molecule, and the amount of these gases is preferably 0.0001 to 5.0% by volume, preferably based on the total gas. Is 0.001 to 3.0% by volume. By containing these gases, the oxygen concentration in the transparent conductive film can be adjusted and the conductivity can be improved.

  The carbon content of the transparent conductive film thus formed is preferably in the range of 2 to 0.01 atomic%, and the nitrogen content in the film is preferably in the range of 2 to 0.01 atomic%.

  The formed transparent conductive film uses a discharge gas containing 50% or more of nitrogen, and contains an inorganic gas containing oxygen atoms such as nitrogen dioxide (for example, nitrogen dioxide) as the oxidizing gas in the above range. Thereby, carbon content and nitrogen content can be made into the said range, a preferable carrier density and carrier mobility can be obtained, and the electrical conductivity of a transparent conductive film improves. When contamination (impurity components) such as carbon and nitrogen exceeds this range, the components derived from the mixed carbon and nitrogen trap the carriers in the film, lower the carrier density and mobility, and the resistivity. Will increase.

<< Measurement of carbon content and nitrogen content >>
The carbon content or nitrogen content in these thin films was determined using an XPS surface analyzer at the stage where the films were formed. There are no particular limitations on the XPS surface analyzer used, and any model can be used, but in the examples of the present invention, ESCALAB-200R manufactured by VG Scientific was used. The measurement was performed using Mg for the X-ray anode and an output of 600 W (acceleration voltage: 15 kV, emission current: 40 mA). The energy resolution was set to be 1.5 to 1.7 eV when defined by the half width of a clean Ag3d5 / 2 peak.

  Before the measurement, the surface layer corresponding to 10 to 20% of the thickness of the thin film was removed by etching in order to remove the influence of contamination. For the removal of the surface layer, it is preferable to use an ion gun that can use rare gas ions. As the ion species, He, Ne, Ar, Xe, Kr, or the like can be used. In this measurement, the surface layer was removed using Ar ion etching.

  First, the range of binding energy from 0 eV to 1100 eV was measured at a data acquisition interval of 1.0 eV to determine what elements were detected.

  Next, with respect to all the detected elements except for the etching ion species, the data capture interval was set to 0.2 eV, and the photoelectron peak giving the maximum intensity was subjected to narrow scan, and the spectrum of each element was measured. The obtained spectrum is preferably COMMON DATA PROCESSING SYSTEM (Ver. 2.3 or later) manufactured by VAMAS-SCA-JAPAN in order not to cause a difference in the content calculation result due to a difference in measuring apparatus or computer. ) After transferring to the above, processing was performed with the same software, and values of carbon and nitrogen content were determined as atomic concentration (at%).

  Further, the ratio of tin to indium can also be obtained as the ratio of the atomic number concentration obtained from the above result.

  Further, before performing the quantitative process, the calibration of the Scale for each element was performed, and a 5-point smoothing process was performed. In the quantitative process, the peak area intensity (cps × eV) from which the background was removed was used.

  The Shirley method was used for background processing.

  For the Shirley method, see D.C. A. Shirley, Phys. Rev. , B5, 4709 (1972).

  The film thickness of the metal oxide or metal composite compound transparent conductive film formed is preferably in the range of 0.1 to 1000 nm.

  The transparent conductive film obtained by the method for producing an article having the transparent conductive film of the present invention has a characteristic of having high carrier mobility. As is well known, the electrical conductivity of the transparent conductive film is represented by the following formula (1).

σ = n × e × μ (1)
Here, σ is the electric conductivity, n is the carrier density, e is the quantity of electrons, and μ is the carrier mobility. In order to increase the electrical conductivity σ, it is necessary to increase the carrier density n or the carrier mobility μ. However, as the carrier density n is increased, the reflectivity increases from around 2 × 10 ²¹ cm ⁻³ , so that it is transparent. Sex is lost. Therefore, in order to increase the electrical conductivity σ, it is necessary to increase the carrier mobility μ. According to the method for forming a transparent conductive film of the present invention, it is possible to form a transparent conductive film having a carrier mobility μ close to that of a transparent conductive film formed by a DC magnetron sputtering method by optimizing the conditions. It has been found.

The carrier mobility of the transparent conductive film prepared by a commercially available DC magnetron sputtering method is about 30 cm ² / sec · V. However, according to the conductive film formation method of the present invention, a transparent conductive film having a carrier mobility exceeding that of the transparent conductive film formed by the DC magnetron sputtering method using a commercially available apparatus is formed by optimizing the conditions. It turns out that it is possible.

By using the conductive film forming method of the present invention, a transparent conductive film having a carrier mobility of 10 cm ² / V · sec or more can be obtained.

Since the method for forming a transparent conductive film of the present invention has a high carrier mobility μ, a transparent conductive film having a specific resistance value of 1 × 10 ⁻³ Ω · cm or less can be obtained without doping. The specific resistance can be further lowered by doping to increase the carrier density n. In addition, by using a thin film forming gas that increases the specific resistance value as necessary, a transparent conductive film having a high specific resistance value of 1 × 10 ⁻² Ω · cm or more can be obtained. Examples of the thin film forming gas used for adjusting the specific resistance value of the transparent conductive film include titanium triisopropoxide, tetramethoxysilane, tetraethoxysilane, and hexamethyldisiloxane.

The transparent conductive film obtained by the method for forming a transparent conductive film of the present invention has a carrier density n of 1 × 10 ¹⁹ cm ⁻³ or more, more preferably 1 × 10 ²⁰ cm ⁻³ or more under more preferable conditions. Transparency does not decrease.

  In the present invention, the specific resistance value is determined by a four-terminal method in accordance with JIS-R-1637. In addition, for example, Mitsubishi Chemical Loresta-GP and MCP-T600 were used for the measurement.

  Further, the carrier density and mobility can be obtained by performing measurement by the van der Pauw method using, for example, the Sanwa Radio Instrument Laboratory M1-675 system.

  One of the excellent effects of the present invention is etching. When various display elements are used as electrodes, a patterning process for drawing a circuit on a substrate is indispensable, and whether patterning can be easily performed is an important issue in terms of process suitability. In general, patterning is often performed by a photolithography method, and a portion that does not require conduction is dissolved and removed by etching. Therefore, the speed of dissolution of the portion by the etchant and the absence of residue are important issues. ing. As the etching solution, nitric acid, hydrochloric acid, mixed acid of hydrochloric acid and nitric acid, hydrofluoric acid, ferric chloride aqueous solution or the like is usually used, and these wet etching methods are mainstream.

  As the transparent conductive thin film, the thickness of the formed oxide or composite oxide thin film is preferably in the range of 0.1 to 1000 nm.

  The base material which forms the transparent conductive film concerning this invention is demonstrated.

  The substrate for forming the transparent conductive film according to the present invention is not particularly limited as long as a thin film can be formed on the surface thereof. There is no limitation on the form or material of the substrate as long as the substrate is exposed to a plasma mixed gas to form a uniform thin film. Resin films, resin sheets (plates), and glass plates are suitable for the present invention.

  Since the transparent conductive film forming method of the present invention can form a high-performance transparent conductive film even when the substrate surface temperature is relatively low, it is preferable to perform plasma discharge treatment at a substrate surface temperature of 300 ° C. or less. A transparent conductive film can be easily formed on the surface of other resin films, resin sheets, resin lenses, etc. at a relatively low temperature without deformation of the material.

  Since the resin film can form a transparent conductive film by continuously transferring between or in the vicinity of the electrodes of the atmospheric pressure plasma discharge processing apparatus according to the present invention, it is not a batch type like a vacuum system such as sputtering. Suitable for mass production, suitable as a continuous and highly productive production method.

  Resin films, resin sheets, resin lenses, resin moldings and other molded materials include cellulose triacetate, cellulose diacetate, cellulose acetate propionate or cellulose acetate such as cellulose acetate butyrate, polyethylene terephthalate and polyethylene naphthalate. Polyester such as Polyethylene, Polyethylene such as Polypropylene, Polypropylene, Polyvinylidene chloride, Polyvinyl chloride, Polyvinyl alcohol, Ethylene vinyl alcohol copolymer, Syndiotactic polystyrene, Polycarbonate, Norbornene resin, Polymethylpentene, Polyetherketone, Polyimide, Polyether Sulfone, polysulfone, polyetherimide, polyamide, fluororesin, polymethylacrylate , It can be mentioned acrylate copolymer and the like.

  These materials can be used alone or in combination as appropriate. Among them, ZEONEX and ZEONOR (made by Nippon Zeon Co., Ltd.), amorphous cyclopolyolefin resin film ARTON (made by Nippon Synthetic Rubber Co., Ltd.), polycarbonate film Pure Ace (made by Teijin Ltd.), cellulose triacetate film Konica Commercial products such as Tack KC4UX and KC8UX (manufactured by Konica Corporation) can be preferably used. Furthermore, even for materials with a large intrinsic birefringence such as polycarbonate, polyarylate, polysulfone, and polyethersulfone, conditions such as solution casting film formation, melt extrusion film formation, and further stretching conditions in the vertical and horizontal directions What can be used can be obtained by setting etc. suitably.

  Among these, a cellulose ester film that is optically close to isotropic is preferably used for the transparent conductive film of the present invention. As the cellulose ester film, the cellulose triacetate film and the cellulose acetate propionate are preferably used as described above. As the cellulose triacetate film, commercially available products such as Konicatak KC4UX and KC8UX are useful.

  Those obtained by coating gelatin, polyvinyl alcohol, acrylic resin, polyester resin, cellulose ester resin or the like on the surface of these resins can also be used. Further, an antiglare layer, a clear hard coat layer, an antifouling layer or the like may be provided on the thin film side of these resin films. Moreover, you may provide an adhesive layer, an alkali barrier coat layer, a gas barrier layer, a solvent resistant layer, etc. as needed.

  A glass plate or a resin sheet (plate) can be used as the base material for each leaf. The resin sheet (plate) is the same as the above resin, but examples of the glass plate include soda lime glass, borosilicate glass, ultra-high purity glass, and crystal glass. Moreover, the base material which concerns on this invention is not limited to said description. The film thickness is preferably 10 to 1000 μm, more preferably 40 to 200 μm. Moreover, as a film thickness of a glass plate-shaped thing, 0.1-2 mm is preferable.

  Hereinafter, the present invention will be specifically described with reference to the following examples, but is not limited thereto.

〔Evaluation item〕
<< Transmissivity >>
In accordance with JIS-R-1635, measurement was performed using a spectrophotometer U-4000 type manufactured by Hitachi, Ltd. The wavelength of the test light was 550 nm.

<Specific resistance value>
According to JIS-R-1637, it calculated | required by the four terminal method. In addition, Mitsubishi Chemical Loresta-GP and MCP-T600 were used for the measurement.

《Moisture and heat resistance (robustness)》
A sample left at 23 ° C. and 55% RH was left for 240 hours using a thermostat at 60 ° C. and 90% RH, and then left again at 23 ° C. and 55% RH for humidification and specific resistance before and after heating. The values (Ωcm) were R0 and R, respectively, and the rate of change R / R0 was used as an indicator of robustness. The specific resistance value was measured by the same method as the specific resistance value.

《Pencil hardness test》
The hardness of the surface of an article having a transparent conductive film was measured and evaluated according to the pencil hardness measurement described in JIS K5200.

《Carrier density, mobility》
Measurement was performed by the van der Pauw method using the Sanwa Radio Sokki Laboratory M1-675 system, and the carrier density and carrier mobility were determined.

<< Measurement of carbon content and nitrogen content >>
The film composition and carbon content were determined using an XPS surface analyzer. There is no particular limitation on the XPS surface analyzer used, and any model can be used. In this example, ESCALAB-200R manufactured by VG Scientific, Inc. was used. The measurement was performed using Mg for the X-ray anode and an output of 600 W (acceleration voltage: 15 kV, emission current: 40 mA). The energy resolution was set to be 1.5 to 1.7 eV when defined by the half width of a clean Ag3d5 / 2 peak.

  Before the measurement, the surface layer corresponding to 10 to 20% of the thickness of the thin film was removed by etching in order to remove the influence of contamination. For the removal of the surface layer, it is preferable to use an ion gun that can use rare gas ions. As the ion species, He, Ne, Ar, Xe, Kr, or the like can be used. In this measurement, the surface layer was removed using Ar ion etching.

  First, the range of binding energy from 0 eV to 1100 eV was measured at a data acquisition interval of 1.0 eV to determine what elements were detected.

  Next, with respect to all the detected elements except for the etching ion species, the data capture interval was set to 0.2 eV, and the photoelectron peak giving the maximum intensity was subjected to narrow scan, and the spectrum of each element was measured. The obtained spectrum is preferably COMMON DATA PROCESSING SYSTEM (Ver. 2.3 or later) manufactured by VAMAS-SCA-JAPAN in order not to cause a difference in the content calculation result due to a difference in measuring apparatus or computer. ) After transferring to the above, processing was performed with the same software, and values of carbon and nitrogen content were determined as atomic concentration (at%).

  Further, the ratio of tin to indium can also be obtained as the ratio of the atomic number concentration obtained from the above result.

  Further, before performing the quantitative process, the calibration of the Scale for each element was performed, and a 5-point smoothing process was performed. In the quantitative process, the peak area intensity (cps × eV) from which the background was removed was used.

  The Shirley method was used for background processing.

  For the Shirley method, see D.C. A. Shirley, Phys. Rev. , B5, 4709 (1972).

Examples Hereinafter, the present invention will be described by way of examples, but the present invention is not limited thereto.

  Using an atmospheric pressure plasma discharge processing apparatus as shown in FIG. 1, a transparent conductive film was formed on a glass plate as a base material mounted on a movable frame (not shown).

[Production of electrodes]
<Counter electrode>
Two sets of fixed electrodes as shown in FIG. 1 were prepared and used as counter electrodes. As the metal base material, two titanium tube T64 pieces having a length of 50 mm, a width of 600 mm, and a height of 50 mm and a thickness of 7 mm and having a hollow inside are produced. Electrodes 11 and 12 were used. The gap was a 1 mm slit so that the surfaces of the first electrode 11 and the second electrode 12 were parallel, and this slit was the counter electrode 13.

  A gas inlet as shown in FIG. 1 was joined on the slit between the electrodes.

<Moving platform>
Prepare a flat plate of length 600mm, width 600mm, thickness 50mm covered with an insulator, and attach screws suitable for the two screw screw tracks of the moving means on both sides of the flat plate. I was able to move.

[Atmospheric pressure plasma discharge treatment equipment]
As shown in FIG. 1, the gap (processing space) between the bottom surface of the counter electrode (upper and lower sides of the paper) and the glass plate base material on the movable frame was 1.5 mm.

  A first power source 21 was connected to the first electrode 11, and a first filter 23 was installed between them. The first filter 23 is made difficult to pass the current from the first power supply 21 and the current from the second power supply 22 is easily passed. The second filter 24 is made difficult to pass the current from the second power supply. Each of them was installed to facilitate the passage of current from the first power source 21. The second electrode 12 and the second power source 22 were connected, and a second filter 24 was installed between them. Each power source and each filter were grounded to earth.

[Production of glass plate having transparent conductive film]
The first power source 21 and the second power source 22 were selected and used so that the relationship between the high frequency voltage and the discharge start voltage was V1>IV> V2. As the substrate, a soda glass plate having a length of 500 mm, a width of 450 mm, and a thickness of 0.5 mm was used. The processing space between the opposing electrodes of the first electrode 11 and the second electrode 12 and on the substrate was set to a pressure of 104 kPa, and a mixed gas containing a discharge gas and a transparent conductive film forming gas was introduced into the interelectrode slit. Temperature adjustment was performed so that both electrodes might be 80 degreeC. A high frequency voltage is applied from the first power source 21 and the second power source 22 to discharge the first electrode with a power density of 7 W / cm ² and a second electrode with a power density of 7 W / cm ^2. The transparent conductive film forming gas is turned into a plasma state and blown out in the form of a jet, and the substrate glass plate F is exposed to the transparent conductive film forming gas G ° in the plasma state. A transparent conductive film was formed on the base glass plate by reciprocating until reaching 80 nm, and a glass substrate having the transparent conductive film was produced.

Samples 1 to 12 were produced by using nitrogen gas as a discharge gas and a high frequency power source A2 as a first power source (frequency ω ₁ = 5 kHz, high frequency voltage V ₁ = 12 kV / mm, output density = 5 W / cm ² ). Further, as the second power source, the high frequency power source B3 (frequency ω ₂ = 13.56 MHz, high frequency voltage V ₂ = 0.5 kV / mm, output density = 5 W / cm ² ) is used, and the metal compound used as the reactive gas Using a mixed gas (MG) in which the gas is changed, the type of the transparent conductive film is changed, and the additive gas used as the reactive gas is oxygen, nitrogen dioxide, carbon dioxide, hydrogen (comparison) (Table) 1). The composition of the mixed gas (MG1, 2, 3) used for forming each transparent conductive film is also shown below. The discharge start voltage of nitrogen gas in this system was 3.7 kV / mm.

For samples 13 and 14, a mixed gas (MG4) having the following composition using helium as the discharge gas was used, and a high frequency power supply JRF-10000 manufactured by JEOL Ltd. was installed between the first electrode and the second electrode. The plasma discharge treatment was performed by supplying power of 5 W / cm ² at a frequency of 13.56 MHz. Oxygen and hydrogen were used as additive gases (described in Table 1).

In addition, as a sample, an ITO film was prepared as a sample by sputtering. That is, the same substrate was mounted on a DC magnetron sputtering apparatus, and the inside of the vacuum chamber was depressurized to 1 × 10 ⁻⁵ torr or less. A sputtering target having a composition of indium oxide: tin oxide = 95: 5 was used. Thereafter, a mixed gas of argon gas and oxygen gas (Ar: O ₂ = 1000: 3) was introduced until 1 × 10 ⁻³ Pa, and film formation was performed at a sputtering output of 100 W and a substrate temperature of 100 ° C. .

  Moreover, the plasma discharge apparatus used for the preparation of Sample 1 was used as Sample 16, except that the glass substrate was replaced with an amorphous cyclopolyolefin resin film (ARTON® film manufactured by JSR Corporation: thickness 100 μm). Except for the above, an ITO film was prepared in the same manner as Sample 1.

  As Sample 17, an ITO film was prepared in the same manner as Sample 16, except that the base material was changed to ZEONOR (R) ZF16 (thickness: 100 μm) manufactured by Nippon Zeon.

  An ITO film was prepared in the same manner as Sample 18 except that the sample 16 was replaced with a polycarbonate film (Pure Ace (R) manufactured by Teijin Limited: thickness 100 μm) formed by casting.

  As sample 19, an ITO film was prepared in the same manner as in sample 16, except that the base material was changed to a triacetyl cellulose film (TAC; thickness: 100 μm).

  As the sample 20, a wound-up magnetron sputtering apparatus having a vacuum chamber, a sputtering target, and a gas introduction system was used, and an amorphous cyclopolyolefin resin film (ARTON® film manufactured by JSR Corporation) used in the sample 16 according to the following procedure: An ITO film was formed on the thickness (100 μm).

That is, a film was introduced into the apparatus, and the inside was depressurized to 4.00 × 10 ⁻⁴ Pa. Note that a sputtering target having a composition of indium oxide: tin oxide 95: 5 was used. Thereafter, the film was rewound and degassed. Next, a mixed gas of argon gas and oxygen gas (Ar: O ₂ = 98.8: 1.2) was introduced until 1 × 10 ⁻³ Pa, the temperature of the main roll was set to room temperature, and the film feeding speed was set to Film formation was performed at 0.1 m / min and a power density of 1 W / cm ² to produce an ITO film.

  The composition of the mixed gas (MG1-4) used for forming each of the transparent conductive films is shown below.

  Further, in the production of the samples 1 to 12, the vicinity of the discharge space is on the surface (outside) opposite to the discharge surface of the first and second electrodes 11 and 12, as shown in FIG. Nitrogen gas is introduced at an amount of 10 L / min so as to form an air curtain that blocks the discharge space from outside air from a plurality of outlets L provided at both end faces of the electrode so as to eliminate the influence of the surrounding atmosphere. I made it.

<Mixed gas composition>
(MG1; ITO)
Discharge gas: Nitrogen gas 98.45% by volume
Transparent conductive film forming gas 1: tris (2,4-pentanedionate) indium
1.2% by volume
Transparent conductive film forming gas 2: dibutyldiacetoxytin 0.05% by volume
Additive gas (oxidizing gas) 0.3% by volume
(MG2; IZO)
Discharge gas: Nitrogen gas 98.3% by volume
Gas for forming transparent conductive film 1: Indium tris (2,4-pentanedionate)
1.2% by volume
Transparent conductive film forming gas 2: Zinc bis (2,4-pentanedionate) 0.2% by volume
Additive gas 0.3% by volume
(MG3; FTO)
Discharge gas: Nitrogen gas 98.65% by volume
Gas for forming transparent conductive film 1: Tin bis (2,4-pentanedionate) 1.2% by volume
Gas for forming transparent conductive film 2: 0.01% by volume of tetrafluoromethane
Additive gas 0.14% by volume
(MG4; ITO)
Discharge gas: Helium gas 98.65% by volume
Transparent conductive film forming gas 1: tris (2,4-pentanedionate) indium
1.2% by volume
Transparent conductive film forming gas 2: dibutyldiacetoxytin 0.05% by volume
Additive gas 0.1% by volume
For Samples 1-15, 27-30, and Comparative Example 9, the carbon content and nitrogen content of the obtained transparent conductive film were measured as atomic concentration% (atomic concentration (%)) by the above method, The specific resistance value, the carrier density, the carrier mobility, the transmittance, the robustness of the specific resistance value, and the pencil hardness were evaluated, and the results are shown in Table 1 below.

(result)
Using a first power source and a second power source, an oxygen-containing inorganic gas is used as an additive gas, and plasma discharge treatment is performed as a frequency and a high-frequency voltage suitable for the present invention, so that a transparent conductive film is formed of ITO, IZO, or FTO film. By forming the ITO film, the ITO film, the IZO film, and the FTO film having a dense film, low resistance, excellent robustness, and good etching characteristics could be formed (Samples 1 to 9). On the other hand, those using hydrogen as the additive gas could only obtain ITO films, IZO films and FTO films having high specific resistance values, poor robustness, low hardness and poor etching characteristics.

  Similarly, the conductive film formed on the plastic film substrate has a high robustness and good properties.

It is the schematic which showed an example of the atmospheric pressure plasma discharge processing apparatus of the jet system useful for this invention. It is a figure which shows the example of the plasma discharge processing apparatus concerning another this invention. It is the schematic which shows an example of the atmospheric pressure plasma discharge processing apparatus of the system which processes a base material between the electrodes which oppose. It is a perspective view which shows an example of the structure of the electroconductive metal base material of the roll rotating electrode shown in FIG. 3, and the dielectric material coat | covered on it. It is a perspective view which shows an example of the structure of the electroconductive metal preform | base_material of a rectangular tube type electrode, and the dielectric material coat | covered on it. It is the schematic which shows the example which provided the cover in the side surface of the plasma discharge processing container, and made the structure which can interrupt | block the electrode side surface from external atmosphere.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Plasma discharge processing apparatus 11 1st electrode 12 2nd electrode 20 Electric field application means 21,41 1st power supply 22,42 2nd power supply 23,43 1st filter 24,44 21st filter 32 Discharge space 35 Roll rotating electrode 36 Angle Cylindrical fixed electrode group

Claims (22)

Under an atmospheric pressure or a pressure near atmospheric pressure, a reactive gas and a discharge gas are introduced into the discharge space between the electrodes, a high frequency electric field is applied between the electrodes to form a plasma state, and the substrate is In a method of forming a transparent conductive film by exposing to a reactive gas in a plasma state and forming a transparent conductive film on a substrate, the reactive gas contains an inorganic gas having at least one oxygen atom in the molecule and an organometallic compound A method for forming a transparent conductive film, which is a gas and the discharge gas is nitrogen. The oxygen concentration in the atmosphere around the discharge space including the space formed between the electrodes to which the high-frequency electric field is applied and the space in which the reactive gas in the plasma state formed by the applied high-frequency electric field is in contact with the substrate It is 5 volume% or less, The transparent conductive film formation method of Claim 1 characterized by the above-mentioned. The method for forming a transparent conductive film according to claim 1, wherein the organometallic compound is an organometallic compound represented by the following general formula 1 or general formula 2.

[In General Formulas 1 and 2, M represents In, Sn, Zn, R ₁ and R ₂ each represents an alkyl group, an aryl group, or an alkoxyl group that may have a substituent, and R represents a hydrogen atom, Represents a substituent, and R may combine with R ₁ and R ₂ to form a ring. R ₃ represents an alkyl group or an aryl group each optionally having a substituent. n1 represents an integer, and n2 represents an integer. ] The high-frequency electric field is a superposition of a first high-frequency electric field and a second high-frequency electric field;
Said first of said second high-frequency electric field than the frequency omega ₁ of the high-frequency electric field frequency omega ₂ is high, the strength V ₁ of the first high frequency electric field, strength V ₂ and the discharge start of the second high-frequency electric field The relationship with the electric field strength IV is
V ₁ ≧ IV> V ₂
Alternatively, the transparent conductive film forming method according to claim ₁ , wherein V ₁ > IV ≧ V ₂ is satisfied. The method for forming a transparent conductive film according to claim 4, wherein the discharge space includes a first electrode and a second electrode facing each other. The method for forming a transparent conductive film according to claim 4 or 5, wherein an output density of the second high-frequency electric field is 50 W / cm ² or less. The method for forming a transparent conductive film according to claim 6, wherein an output density of the second high-frequency electric field is 20 W / cm ² or less. The method for forming a transparent conductive film according to claim 4, wherein an output density of the first high-frequency electric field is 1 W / cm ² or more. The method for forming a transparent conductive film according to any one of claims 4 to 8, wherein an output density of the first high-frequency electric field is 50 W / cm ² or less. The method for forming a transparent conductive film according to any one of claims 4 to 9, wherein at least the second high-frequency electric field is a sine wave. The voltage for forming the first high-frequency electric field is applied to the first electrode, and the voltage for forming the second high-frequency electric field is applied to the second electrode. 11. The transparent conductive film forming method according to any one of 10 above. The method for forming a transparent conductive film according to any one of claims 4 to 11, wherein 90 to 99.9% by volume of the total amount of gas supplied to the discharge space is discharge gas. The method for forming a transparent conductive film according to any one of claims 4 to 12, wherein an output density of the second high-frequency electric field is 1 W / cm ² or more. The method for forming a transparent conductive film according to claim 4, wherein the frequency ω ₁ is 200 kHz or less. The method for forming a transparent conductive film according to claim 4, wherein the frequency ω ₂ is 800 kHz or more. The method for forming a transparent conductive film according to claim 1, wherein the surface temperature of the substrate exposed to the reactive gas in the plasma state is 300 ° C. or less. The method for forming a transparent conductive film according to claim 1, wherein the inorganic gas having at least one oxygen atom in the molecule is N ₂ O gas. The specific resistance value of the transparent conductive film is 1 × 10 ⁻³ Ω · cm or less, the carrier mobility is 10 cm ² / V · sec or more, and the carrier density is 1 × 10 ¹⁹ cm ⁻³ or more. The transparent conductive film forming method according to claim 1, wherein the transparent conductive film is formed. The method for forming a transparent conductive film according to claim 1, wherein the carbon content of the transparent conductive film is 2 to 0.01 atomic%. The method for forming a transparent conductive film according to claim 1, wherein the transparent conductive film has a nitrogen content of 2 to 0.01 atomic%. The transparent conductive film is any one of indium oxide, tin oxide, zinc oxide, fluorine-doped tin oxide, Al-doped zinc oxide, Sb-doped tin oxide, ITO, and an In ₂ O ₃ —ZnO-based amorphous transparent conductive film. The method for forming a transparent conductive film according to claim 1, wherein the transparent conductive film is formed. The transparent conductive film forming method according to any one of claims 1 to 21, wherein the base material on which the transparent conductive film is formed is a transparent resin film or glass.

Images